All week long for World Space Week, we will be posting exclusive excerpts from Chris Impey and Holly Henry’s new book, Dreams of Other Worlds: The Amazing Story of Unmanned Space Exploration. Each day will include an excerpt from a different chapter about a different unmanned spacecraft, along with a picture of the craft that doubles as an iPhone background!

Today’s excerpt is from Chapter 2, and it discusses what it was like when, in 1976, we first landed a spacecraft on Mars.

Tomorrow will bring another chapter and another adventure, so stay tuned!

The Vikings Reach Mars

On July 20, 1976, a small spacecraft emerged from a cloudless, apricot-colored Martian sky and fell toward the western Chryse Planitia, the “Golden Plain.” Its heat shield glowed as it buffeted through the tenuous atmosphere.27 About four miles up, the parachutes deployed, the heat shield was jettisoned, and three landing legs unfolded like a claw. At one mile up, the retrorockets fired, and less than a minute later the Viking 1 lander decelerated to six miles per hour, reaching the surface with a slight jolt.28 It was a landmark of technological prowess, the first time humans had ever soft-landed an emissary on another planet. The twin Viking missions were the most complex planetary probes ever designed. Their total price tag was around $1 billion, equivalent to $4 billion today after adjusting for inflation. That can be compared to the $80 million cost of Mariner 4. Mission planners were well aware of the challenges; the Soviets had previously failed four times to soft land on Mars.29 Each Viking consisted of an orbiter designed to image the planet and a lander equipped to carry out detailed experiments on the surface.30 For the most part, the hardware worked flawlessly, but there were tense moments for the engineers and scientists on the team. After ten months and 100 million miles of traveling, the Vikings reached Mars two weeks apart.

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